Flame retardants in the South African indoor environment

Abstract

Flame retardants (FRs), such as brominated flame retardants (BFRs), organophosphorus flame retardants (OPFRs), and chlorinated paraffins (CPs) are commonly used in consumer products such as electrical and electronic equipment, furniture, carpets, insulation materials and other commercial products. Due to their unique physiochemical properties, these compounds are useful for the intended purpose to reduce product flammability, and to meet fire safety requirements. The disadvantage is that a number of these FRs end up in the environment and several are also toxic and bioaccumulate in organisms. Developing countries in Africa have limited facilities that specialise in FR analysis. The literature review showed that the analyses in Africa were mainly targeting BFRs. BFR levels were reported for various environmental compartments, whereas there is insufficient data on the levels and occurrence of CPs and OPFRs. In this study, analytical methods for the various FR classes were developed and/ or implemented to provide reliable data for BFR, OPFRs, and CPs in South African environmental matrices. Screening analysis using cat hair as matrix, allowed us to identify FRs and other organohalogenated compounds (OHCs). More than seventy OHCs were identified, and included known FRs, and legacy contaminants such as polychlorinated biphenyls (PCBs) and pesticides. Concentrations for BFRs, OPFRs, and CPs were further determined in indoor dust and hair samples obtained for some of the indoor pet cats. To support the quality of the data the sources of uncertainty were identified during method validation for BFRs and OPFRs. The major contributions to the combined uncertainties were associated with recovery and repeatability. The South African indoor environment shows high levels of CPs followed by OPFRs and BFRs. This first report on CPs in South Africa shows that medium-chain CPs (MCCPs) are the dominant CP group while concentrations of short-chain CPs (SCCPs) are higher than for long-chain CPs (LCCPs). This study also shows for the first time that, of the three main OPFR groups, chloroalkyl-OPFRs (Cl-OPFRs) dominate the indoor dust profile with high contributions from tris(2-chloroisopropyl) phosphate (TCIPP). BFR concentrations are relatively low, compared to those of OPFRs and CPs and dominated by BDE209. Although hair and indoor dust samples showed comparable FR profiles, shorter chain CPs with lower chlorine substitution, alkyl-OPFRs and alternative BFRs were prominent in cat hair samples, whereas the Cl-OPFR contribution was higher in dust. As dust is widely used as a measure for indoor exposure, the use of cat hair provides specific information on indoor exposure and can be seen as a non-invasive passive sampling method to continued exposure of FRs in the indoor environment. An estimation of the human exposure to OPFRs and BFRs via dust ingestion showed a high ingestion exposure estimate for TCIPP, and exposures for cats could be up to three times higher than estimated for toddlers. The high levels of CPs and the carcinogenic chlorinated-OPFRs are a cautionary warning that warrants more attention to these compounds when the reduction of indoor contamination is considered. Toddlers share the same environment as cats and exposure could result in health risks for children.